This invention relates to fluid ejection devices. In some fluid ejection devices, fluid droplets are ejected from one or more nozzles onto a medium. The nozzles are fluidically connected to a fluid path that includes a fluid pumping chamber. The fluid pumping chamber can be actuated by an actuator, which causes ejection of a fluid droplet. The medium can be moved relative to the fluid ejection device. The ejection of a fluid droplet from a particular nozzle is timed with the movement of the medium to place a fluid droplet at a desired location on the medium. In these fluid ejection devices, it is usually desirable to eject fluid droplets of uniform size and speed and in the same direction in order to provide uniform deposition of fluid droplets on the medium.